Warning: Images of human remains feature in this post

If you’re involved in the heritage sector then chances are you’ve seen a three dimensional (3D) model of an archaeological site, feature or artefact that you can view and interact with on a computer screen or mobile device. It’s likely this was created using SfM, which operates under the basic principle that 3D structure can be resolved using overlapping images. Photogrammetry is the science of making measurements from photographs. Therefore, SfM photogrammetry is the use of photographs to accurately record 3D models from which measurements and details can be recorded. I could go into more detail regarding the technique itself works but for now lets just assume it’s tantamount to magic!

Capturing a collard urn

We’ve been exploring the possible uses here at AAL for a couple of years now after initially learning about its potential from the master of archaeological photography, Adam Stanford (http://www.aerial-cam.co.uk/). Initially we trialled the technique out in the field for the recording of skeletons and masonry because these are two often poorly recorded feature-types; that and our office at the time was somewhat unsuitable for artefact recording (to put it mildly) and my spare bedroom/dark room at home was full of kittens. What we found was that, if recorded properly on site, the technique allowed for a more accurate record of the feature from which a traditional illustration could be made and disseminated to specialists to aid in their assessment/analysis.

Example of a record using SfM on site

It also allowed us to revisit these features from the comfort of the office (the new one, not the old one) and examine them in closer detail than we had time for on site.

Masonry recording

By the time my fieldwork marathon was complete we had a new head office in Lincoln with plenty of space for us to experiment with SfM on artefacts. Trial and error was key here, and there were many failed attempts before finally working out a methodology fit for the task (credit must go to Hugh Fiske for providing the inspiration needed to complete this and I’m sure you’ll agree he’s made some beautiful models, http://www.archaeo3d.me.uk/)

Part of the company ethos here focusses on training for all, and as soon as we were happy with the workflow we began training others in this recoding technique. Currently we’re building up a portfolio of models so that in the near-future we can showcase them online for everyone to access, so watch this space.

Chris training Andrea and Charlotte in Structure from Motion